It is well known that active oxygen-releasing peroxide compounds are effective bleaching agents. These compounds are frequently incorporated in detergent compositions for stain and soil removal. They have, however, an important limitation: the activity is extremely temperature-dependent. Thus, active oxygen-releasing bleaches are essentially only practical when the bleaching solution is heated above 60.degree. C. At a bleach solution temperature of about 60.degree. C., extremely high amounts of the active oxygen-releasing compounds must be added to achieve any bleaching effect. This is both economically and practically disadvantageous. As the bleach solution temperature is lowered below 60.degree. C., peroxide compounds, e.g. sodium perborate, are rendered ineffective, regardless of the level of peroxide compound added to the system. The temperature dependency of peroxide compounds is significant because such bleach compounds are commonly used as a detergent adjuvant in textile wash processes that utilize an automatic household washing machine operating at wash water temperatures of 60.degree. C. and therebelow. Such wash temperatures are utilized because of textile care and energy considerations. Consequently, a constant need has developed of substances which render peroxide compound bleaches more effective at bleach solution temperatures below 60.degree. C. These substances are generally refered to in the art as bleach precursors, promoters or activators.
Normally, bleach precursors are used in conjunction with peroxide compounds, e.g. persalts, which are capable of releasing hydrogen peroxide in aqueous solution, perborate being the most widely used persalt.
Typically, the precursor is a reactive compound such as a carboxylic acid ester that in alkaline solution containing a source of hydrogen peroxide, e.g. a persalt, such as sodium perborate, will generate the corresponding peroxyacid. The reaction involves nucleophilic substitution onto the precursor by hydroperoxy anions (HOO.sup.-) and is facilitated by precursors having good leaving groups. Often the reaction is referred to as a perhydrolysis.
Examples of bleach precursors are carboxylic esters as disclosed in UK patent specification 836,988; EP-A-0098129 and EP-A-0120591; organic acyl amides as disclosed in UK patent specification 907,356; and organic carbonate esters as disclosed in U.S. Pat. Nos. 3,256,198 and 3,272,750. Quaternary ammonium peroxycarboxylic acid precursors are also known from UK patent specification 1,382,594. The compounds as described in this prior art reference are of the formula: ##STR1## wherein --(C.sub.n H.sub.2n)-- is an optionally branched chain having n equal to 3 or more, preferably 3 to 25;
R.sub.1 is an optionally substituted alkyl radical containing from 1 to 20 carbon atoms, alkaryl, optionally substituted aryl or polyoxyalkylene radical; PA0 R.sub.2 and R.sub.3 are each lower alkyl or hydroxylalkyl radical containing from 1 to 4 carbon atoms; PA0 or two or more of R.sub.1, R.sub.2 and R.sub.3 together with the N-atom form an optionally substituted, nitrogen-containing heterocyclic ring system; PA0 R.sub.4 is an optionally substituted phenyl group; PA0 X is chlorine or bromine. PA0 N-octyl, N,N-dimethyl N-10 carbophenoxydecyl ammonium chloride (ODC); PA0 N-octyl, N,N-dimethyl N-10 carbophenoxydecyl ammonium bromide (ODB); and PA0 N-10 carbophenoxydecyl pyridinium bromide (PDB) or chloride (PDC). PA0 or two of R.sub.1, R.sub.2 and R.sub.3 together with R.sub.4 and the N-atom form an optionally substituted, nitrogen-containing heterocyclic ring system; PA0 or two or more of R.sub.1, R.sub.2 and R.sub.3 together with the N-atom form an optionally substituted, nitrogen-containing heterocyclic ring system; PA0 R.sub.4 (if not formed into a nitrogen-containing heterocyclic ring system together with R.sub.1 and/or R.sub.2 and/or R.sub.3) is a bridging group selected from ##STR3## wherein each n individually can be 0, 1 or 2; PA0 L is a leaving group, the conjugate acid of which has a pK.sub.a in the range of from 4 to 13, preferably from about 8 to 10; and PA0 Z.sup.- can be a chloride, bromide, hydroxide, nitrate, methosulphate, bisulphate, acetate, sulphate, citrate, borate or phosphate anion. PA0 M is a hydrogen, alkali metal, ammonium, or alkyl or hydroxyalkyl-substituted ammonium cation, which may or may not be present.
Typical quaternary ammonium compounds according to this reference are:
A drawback of these quaternary ammonium compounds of the art is that their effectiveness in wash/bleach solutions is rather inconsistent, which could be caused by the fact that the peroxycarboxylic acids derived therefrom are sensitive to temperature and formulation ingredients.
It is an object of the present invention to provide novel quaternary, ammonium-substituted peroxycarboxylic acid precursors, of which the peracids generated therefrom are more stable to temperature and towards composition ingredients present in the wash/bleach solution.
It is another object of the present invention to provide a detergent bleach composition with a precursor that permits highly effective bleaching over a wide temperature range, including that of under 40.degree. C.